Design: This is a 5-year pilot extension study to allow participants who demonstrated clinical improvement with finasteride for chronic CSC to continue receiving finasteride as an off-label treatment. Study visits will occur every six months over the 5-year duration. Participants will receive finasteride when they have serous fluid present, unless deemed chronic non-responders (defined as serous fluid unchanged as compared to baseline or serous fluid stabilized with no further improvement while on finasteride treatment).